The worldwide prevalence is estimated to be 1.5 billion overweight and 500 million obese individuals′. Overall, more than one out of ten of the world's adult population is obese. In 2010, more than 40 million children under five were overweight2. Once considered a high-income country problem, overweight and obesity are now on the rise in low- and middle-income countries, particularly in urban settings3. Overweight and obesity are the fifth leading risks for global deaths1. At least 2.8 million adults die each year globally as a result of being overweight or obese. In addition, 44% of the diabetes burden, 23% of the ischemic heart disease burden and between 7% and 41% of certain cancer burdens are attributable to overweight and obesity2,4. In June 2013, the American Medical Association officially recognized obesity as a disease5.
There is a great concern globally of this serious health issue, but different strategies have not been successful to reverse the obesity trends among the global population. Neither has the awareness for healthier diet and increased physical activity proved particularly effective. There exist several potential explanations such as: the absence of access to healthy, affordable foods or safe places for physical activity, particularly in lower-income neighbourhoods and communities; the inferiority of freshly prepared foods vs. fast foods or pre-packaged foods in terms of preservation, portability, and palatability; the marketing of mostly unhealthy products by the food and beverage industry; and modern cultural habits that increase sedentary behaviours, degrade eating cadences and locations, and incur excess stress levels and sleep debt1,3. Life-style intervention affecting dietary intake and energy expenditure are important, however, often not enough. It is obvious that obesity should be considered as a chronic, incurable disease, which needs better drug products for a successful treatment6. Therefore, there is a need for a novel safe and efficient medical treatment.
Type 2-diabetes is growing epidemically and this rise is closely associated with obesity. Type 2-diabetes has multiple manifestations and sub-optimal treatment is associated with progressive beta-cell failure. Although lifestyle measures, including eating habits and physical activity, should be first-line treatment, success is difficult to achieve, and pharmaceutical intervention is almost always required7. Before manifest type 2-diabetes is diagnosed, the patients usually have a period of impaired glucose tolerance. If this impaired glucose tolerance, which may precede or follow weight gain, is correctly treated, the progression towards diabetes might be halted or averted8. Current treatment options are limited to lifestyle changes, or secondly metformin. Hence, there is a need for a novel safe and efficient medical treatment.
Yet another indication for this invention would be treatment of overweight/obesity in association with Polycystic Ovary Syndrome (PCOS). Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorders among females and produces symptoms in 5% women of reproductive age (conservative figure9). One of the most common immediate symptoms is insulin resistance. This insulin resistance is often associated with obesity, type 2 diabetes, and high cholesterol levels9. Current recommended pharmacological treatment (in addition to contraceptives) of the obese and/or glucose impaired PCOS patients is limited to metformin10; although current guidelines state that the evidence base is not strong10. Other insulin sensitizers, for example thiazolidinediones, have unwanted risk/benefit ratio and are not recommended10. For the PCOS patients, there is a clinical need for a drug that safely both decreases weight and improves glucose tolerance.
Nonalcoholic steatohepatitis (NASH) is liver inflammation and damage caused by a buildup of fat in the liver. NASH affects 2 to 5 percent of Americans. An additional 10 to 20 percent of Americans have fat in their liver, but no inflammation or liver damage, a condition called “fatty liver.” or NAFLD11. Both NASH and NAFLD are becoming more common, possibly because of the greater number of Americans with obesity11. Currently, no specific therapies for NASH exist, except for lifestyle interventions, so there exists an unmet clinical need.
According to the new International Diabetes Federation (IDF) definition, for a person to be defined as having the metabolic syndrome the person must have: Central obesity plus any two of the following four factors:                raised triglyceride (TG) level or specific treatment for this lipid abnormality        reduced high-density lipoprotein (HDL) cholesterol or specific treatment for this lipid abnormality        raised blood pressure or treatment of previously diagnosed hypertension        raised fasting plasma glucose or previously diagnosed type 2-diabetes        
The present inventors postulate that the proposed product will directly or indirectly affect most of the components of the metabolic syndrome, mainly decreasing weight, improving glucose control, which in turn will lead to improved hepatic fat metabolism with decreased triglycerides concentration. The product is expected to also have direct effect on triglyceride concentration.
Current Treatment Options for Obesity and Overweight
Several pharmacological principles have been considered for treatment of obesity or overweight including increasing energy expenditure (stimulants), suppressing caloric intake (anorectic agents), limit nutrient absorption and modulating insulin production and/or action7,10,12,. Four centrally-acting noradrenergic agents (phentermine, diethylpropion, phendimetrazine, benzphetamine) are FDA-approved for usually less than 12 weeks management of obesity. All were approved before the necessity of long-term treatment for obesity was established. In addition, none were required to meet the current efficacy benchmarks for weight loss relative to placebo (mean weight loss ≥5% more than that of the placebo group or proportion of drug-treated subjects who lose ≥5% of initial weight is ≥35% and approximately double the proportion who lose ≥5% in the placebo group)13. Drugs for weight management that are approved for long-term usually result in, on average, an additional weight loss relative to placebo ranging from ˜3% for orlistat and lorcaserin to 9% for phentermine/topiramate-ER at one year14. Already in 2005, the stimulants, including dinitrophenol, amphetamine and ephedra, were abandoned. Among anorectic agents sibutramine was on the market for a few years before adverse effects led to its removal, together with the short lived appetite suppressor Rimonabant. Lorcaserin is a selective serotonin 2C (5HT2c) receptor agonist that was anticipated to recapitulate the weight loss effects of fenfluramine without its adverse cardiac effects15. Lorcaserin decreased body weight modestly, by about 3.2 kg (˜3.2% of initial body weight) more than placebo16. Among patients with diabetes, lorcaserin treatment led to lower body weight and improved glycated hemoglobin concentrations17. Liraglutide (Saxenda®; liraglutide injection) was approved (both by EMA and FDA) as a treatment option for chronic weight management in addition to a reduced-calorie diet and physical activity. The drug is approved for use in adults with a body mass index (BMI) of 30 or greater (obesity) or adults with a BMI of 27 or greater (overweight) who have at least one weight-related condition such as hypertension, type 2 diabetes, or high cholesterol (dyslipidemia). GLP-1 analogues (such as liraglutide and exenatide) have initially been used as diabetes type-2 medication, but successful weight loss trials have been performed where patients lost 8 kg more after one year on the highest dose of liraglutide; compared to the placebo group which lost 2 kg18. A recently completed phase 3 trial evaluating liraglutide 3.0 mg/day vs. placebo for weight maintenance in 422 non-diabetic overweight and obese patients (72% retention)19. The patients successfully lost ≥5% initial weight during a 4-12 week dietary run-in, and also observed an additional weight reduction of 6.2% in the active treatment group over the ensuing 56 weeks, which ends up in a placebo subtracted-difference of −6.1%19. However, safety concerns exist regarding these drugs, chiefly regarding suggested increased risk of developing pancreatic cancer20. The FDA still approves the use of liraglutide but encourages both prescribers and patients to report possible side effects20.
The tale of liraglutide mimics that of many previous anti-obesity drugs. During the last 20 years, about 10 different drugs have been put out on the market, only to be withdrawn within a few years21. The current alternatives include attempts to limit nutrient (lipids) absorption (orlistat), and perhaps to use compounds affecting insulin (see below). In conclusion: the available pharmaceutical products based on a single unit that possesses a positive benefit-risk ratio for this patient group are very limited.
It has been suggested that a combination of drugs would be successful. For instance, FDA recently approved the first obesity combination with phentermine and topiramate6. Topiramate, an antiepileptic, produces moderate weight loss, but the FDA approval as a single drug for obesity treatment was not pursued by the manufacturer14. When topiramate was combined with phentermine and extensively clinically tested, the safety profile of the combination was confirmed and thus gained FDA approval for marketing. Weight loss averages approximately 13% over 2 years6. Another combination, bupropion and naltrexone)(Mysimba®, produces approximately 6% weight loss in clinical trials14 and has been approved in certain countries. Other single agents and combinations are in clinical trials, but all seem to produce results similar to those discussed above6.
Currently, orlistat (Xenical®) is the only available antiobesity drug worldwide. It is available both in prescription (120 mg) and over-the-counter (60 mg) strength and is given by the oral route. Orlistat is a semi-reversible and local inhibitor of gastric and pancreatic lipases in the GI tract and acts as an antiobesity drug by preventing intestinal absorption of dietary fats (i.e. reducing energy intake). The fraction of the dose absorbed of the highly lipophilic orlistat (log P 8.5) is low (<3%) and accordingly the plasma exposure is low (<5 ng/ml)22. Today, orlistat is available in a conventional relative rapid release oral dosage form. However, orlistat, although safe, is associated with some side-effects that severely hamper compliance. In clinical trials, about 25% or more of the patients complain about GI side-effects including diarrhea, oily spottings and fecal urgency22. This, in conjunction with the rather modest effect on weight (Best case scenario: 10% relative weight loss versus placebo 6% relative weight loss23, makes orlistat in this conventional and relative rapid release dosage form unattractive for the vast majority of obese patients. However, in a recent report FDA clearly stated that orlistat is safe and has clinical benefit24.
Acarbose (Glucobay®) is a competitive α-glucosidase and pancreatic α-amylase inhibitor, which inhibits the hydrolysis of oligosaccharides during GI luminal digestion of a meal25. Acarbose has hydrophilic properties (log P −8.1) and consequently low intestinal permeability, low fraction dose absorbed (<5%), low bioavailability and systemic exposure of acarbose. Acarbose, available in conventional immediate release dosage form, is currently used as a diabetic drug, mainly in Asia, but only scarcely in Western countries. It has not been approved for treatment of obesity.
As with orlistat, a large part of the patients using acarbose reports GI tolerability problems (mainly flatulence, diarrhea as well as GI and abdominal pains)25, which limits its current clinical use in western countries.
There are currently two other α-glucosidase inhibitors on the market, miglitol and voglibose. Miglitol is FDA approved and available in several countries, whereas voglibose is approved only in Japan26. Acarbose, miglitol and voglibose lowers HbA1c to more or less the same extent, with slightly different side effect26. Miglitol is absorbed to 100% and is excreted though the kidneys; whereas voglibose is, in similarity to acarbose, only negligibly absorbed. Voglibose, most probably due to its low dose (0.2 mg voglibose/meal is a common dose) shows lower frequency of GI side effects compared to acarbose; but does not decrease rate of gastric emptying27. So far available studies indicate that all three α-glucosidase inhibitors are safe with no systemic effects26,27. There are also a plethora (>1200 compounds) of identified plant compounds that show varying α-glucosidase inhibitory effects28. Acarbose stands out as it is by far the most clinically used and investigated compound, is approved worldwide and its patent has expired.
There is currently no other lipase inhibitor approved for treatment of obesity, with the possible exception of cetilistat. Cetilistat has been shown to have led to similar weight reduction as orlistat, but with much lower frequency of side effects29. Cetilistat is currently only approved in Japan and FDA approval is pending. There are also some lipase inhibitors from plants30, where a few can be bought as OTC-drugs. Thus, the list of potential lipase inhibitors is very short.
As it appears from the discussion above, there is a need for developing an oral pharmaceutical composition for treatment of obesity or overweight that is more effective, but also has reduced side effects and improved tolerability compared with the products on the market today, especially compared with Xenical® tablets. Such an oral product is expected to have an improve benefit: safety ratio and have a favorable health economic profile.
The present inventors have developed a composition comprising acarbose and orlistat, in a modified release dosage form, which has been designed to release acarbose and/or orlistat in specific parts of the GI tract and at specific amounts and release rates to optimize the digestion enzyme inhibition and nutrient inducing satiety feed-back mechanism. By this design of the dosage form it is possible to expose receptors in the intestine to ligands derived from the ingested diet, such as free fatty acids and hexoses, and then to target an appetite regulating system in this patent application named the gastro-intestinal brake (GI brake, described in more detail below) to obtain improved effect of the treatment and, at the same time, reduce the side-effects. Thus, it is possible to obtain a synergistic effect of the two drug substances with an oral modified-release dosage form. Moreover, it is expected that a suitable effect can be obtained with a reduced amount of orlistat and acarbose compared to the dose used in Xenical® (start dose 120 mg) and Glucobay® (start dose 50 mg), respectively.
There is also a need for providing compositions comprising either orlistat or acarbose, which compositions have suitable properties with respect to release of the drug substance so that the drug substance is released in the relevant parts of the gastrointestinal tract and which compositions lead to reduced side-effects compared to known compositions.
A combination of orlistat and acarbose in an oral pharmaceutical product has been suggested in CN 2011 1195582 (Luan Pharm Group Corp). The combination is provided in the form of tablets. The formulations are designed as traditional tablets without any modification of the release rate for any of the compounds (i.e. acarbose and orlistat) to be able to target the GI brake mechanism(s). As seen from the Examples herein a comparison has been made between a composition of CN 2011 1195582 and the present invention and a markedly different dissolution profile is obtained (eg compare FIGS. 11 and 12 with FIG. 22).
A combination of orlistat and acarbose has also been suggested in EP 0 638 317 (Hoffmann-La Roche). As seen from the Examples herein a comparison has been made between a composition of EP 0 638 317 and the present invention and a markedly different dissolution profile is obtained (eg compare FIGS. 11 and 12 with FIG. 21).